We have recently demonstrated that a number of neurotransmitters (GABA and dopamine) and drugs (benzodiazepines and opiates) radiolabeled to a high specific activity bind to specific receptors or binding sites in the mammalian central nervous system. Using these receptor binding assays, we have already found decreases in 3H-QNB binding in the basal ganglia of patients who died of Huntington's Disease. We have also found increases in 3H-spiroperidol binding in postmortem brain samples of patients who were schizophrenic. In the same brain areas and samples, we also found decreases in 3H-naloxone binding. These preliminary results indicate a possible role of endorphins in neuropsychiatric illness. It is our intention to confirm and extend these initial studies and to examine the mechanism of receptor kinetics and dynamics in postmortem samples of patients suffering various neurological and psychiatric disorders. These studies should yield interesting information to the basic scientists and valuable and life-prolonging information to the clinical scientist who can then provide suitable and effective therapy to the patients suffering these neuropsychiatric disorders.